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  1. #1
    Join Date
    Sep 2007
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    32

    Multiple Rheem Contour t-stats w/ Arzel zoning?

    In a Rheem modulating furnace installation where there is also an Arzel Zoning System, do you use a Countour thermostat in all zones or just in the main zone and std t-stats in other zones)?

    How does the control then work - does it just turn the mod furnace into a 2 or 3 stage from the Arzel board (making a modulating furnace no more advisable than a 2 stage if you use Arzel)?

  2. #2
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    67,876
    One of the Rheem guys will be along shorty.

    But I think you use standard stats in all the zones. And the mod becomes a 2 or 3 stage furnace instead of a mod.
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  3. #3
    Join Date
    Feb 2004
    Location
    Wadsworth, OH
    Posts
    316
    Quote Originally Posted by tgeraci View Post
    In a Rheem modulating furnace installation where there is also an Arzel Zoning System, do you use a Countour thermostat in all zones or just in the main zone and std t-stats in other zones)?

    How does the control then work - does it just turn the mod furnace into a 2 or 3 stage from the Arzel board (making a modulating furnace no more advisable than a 2 stage if you use Arzel)?
    We recommend a contour stat in zone 1 with the "V" terminal wired around the zone panel and directly into the furnace.

    If zone 1 is calling at 70% all other zones will be served at 70%.

    If zone 1 is satisfied than all other zones will be served at 40% furnace capacity.

    You can use a relay powered from any (non contour) thermostats W2 terminal and route the "V" wire through the n/c contacts that would open the "V" wire and run the furnace up tp 100% on a call for 2ns stg ht.

    The issue I have with using the furnaces on-board timing sequence is that it stages the third stage too soon for zoning purposes.

    If you use the W2 relay you might need a bypass duct for some minimal static pressure relief to eliminate noise issues at the registers.
    "When you perceive zoning not as a bandage but as an enhancement, you truly understand the dynamics and limitations of forced air heating and cooling"

  4. #4
    Join Date
    Sep 2007
    Posts
    32
    Quote Originally Posted by jramunni View Post
    If zone 1 is satisfied than all other zones will be served at 40% furnace capacity.
    That's actually of concern to me. There are two bedrooms upstairs on zone 2 that are cold in winter. 40% of the BTUs is probably enough to heat the upstairs, but the cold BRs have the longest duct runs in the house and I think that they would need lots of push from the blower to get the heated air there - as is there's hardly any flow out the vents with a 1200 cfm single stage furnace despite the Arzel system. With a modulating furnace and the Arzel board can you increase the blower speed for a particular zone independent of the BTU modulation? (the proposed mod furnace has greater fan CFM capacity than the current furnace - hoping to help overcome the long branch supply to the cold rooms).

    Obviously there's a whole mess behind the questions...see my other recent thread "Opinions on this system..." for background.

    Thank you!

  5. #5
    Join Date
    Feb 2004
    Location
    Wadsworth, OH
    Posts
    316
    Quote Originally Posted by tgeraci View Post
    With a modulating furnace and the Arzel board can you increase the blower speed for a particular zone independent of the BTU modulation? (the proposed mod furnace has greater fan CFM capacity than the current furnace - hoping to help overcome the long branch supply to the cold rooms).
    NO, blower capacity can not be staged differently than the btu capacity. There might be some way adjust for a higher cfm with 40% btu output. Not Sure!

    Have you tried closing down the bypass?
    "When you perceive zoning not as a bandage but as an enhancement, you truly understand the dynamics and limitations of forced air heating and cooling"

  6. #6
    Join Date
    Sep 2007
    Posts
    32
    Quote Originally Posted by jramunni View Post
    Have you tried closing down the bypass?
    I'm going to try it this afternoon when I get home from work. I'll update after I give that a whirl.

  7. #7
    Join Date
    Sep 2007
    Posts
    32

    Bypass update

    Well I'll be darned. The people who installed the zoning 3 years ago put the byass weight on 180 degrees opposite where it should have gone, and the bypass was open all the time. Fixing it has improved the airflow to the bedrooms (still not fantastic but likely acceptable). So much for "professional" installation. There is one company off my list for future work.

    So, back to the thermostat question...with Arzel and a Rheem Contour when the non-Contour t-stat zone calls for heat it appears from previous replies that it will get call the lowest stage from the Contour furnace. Can it ever get more than the lowest stage? If it could get two or three stages according to need that'd be nice...these bedrooms are exposed on two windy sides and I want to be sure the delivery to them can keep up with the heat loss. If it can't stage up in a zoning scenario (unless the main countour stat calls at the same time) then maybe a simpler two stage furnace makes more sense?

  8. #8
    Join Date
    Feb 2004
    Location
    Wadsworth, OH
    Posts
    316
    glad we checked!

    You can ramp the Mod 90 up tp 100% if a 2 stg stat sends a signal indicating a drop in room temp of more than about 1.5 deg. This done very simply with a relay that opens the "V" signal to the furnace and ramps it to full capacity.
    You can set the Mod-90 up for 3 stgs of heat, but i do prefer the full modulation from the zone with the highest heat load...this can be any one zone.
    "When you perceive zoning not as a bandage but as an enhancement, you truly understand the dynamics and limitations of forced air heating and cooling"

  9. #9
    Join Date
    Jan 2004
    Location
    Here and there
    Posts
    4,803
    Sounds like someone did not evaluate you needs well. Better ducting and or an additional system may have solved the problem areas
    i belong to peta ... people eating tasty animals. all my opinions are just mine.

  10. #10
    Join Date
    Oct 2005
    Location
    MN
    Posts
    133
    jramunni

    Will this wiring scheme also work with the Honeywell Envirazone System? I was going to use an Enviarazone 3 Zone system with VisionPro Stats on a Rheem Mod and just 3 Stage it, but I what your talking about here sounds interesting.

    Frank

  11. #11
    Join Date
    Feb 2004
    Location
    Wadsworth, OH
    Posts
    316
    Frank,

    Not sure about the Evirazone panel...my guess is yes as long as one zone is controlled by the Contour stat and the Vision Pro"s have two stage heat function. I believe they do.

    Do get a quote on an Arzel system also.

    jr
    "When you perceive zoning not as a bandage but as an enhancement, you truly understand the dynamics and limitations of forced air heating and cooling"

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